Process and Burner for Production of Syngas from Hydrocarbons

Abstract

A burner ( 10 ) for the partial oxidation of a hydrocarbon feedstock, comprising a combustion chamber and a pre-mixing chamber (E), and a plurality of annular passages for feeding fuel and oxidizer to the combustion chamber, said plurality of annular passages comprising at least a first annular passage for the fuel, and at least a second coaxial annular passage for the oxidizer, producing a layered flow into the premixing chamber (E). In a preferred embodiment the burner has an annular passage ( 1 ) for fuel or oxidizer surrounded by two other passages ( 2 and 3 ) for the oxidizer or fuel, respectively; in a further embodiment a start-up burner ( 20 ) is integrated with the main process burner, said start-up burner having a combustion chamber (L), a main hub (G) and a swirler (H), and providing a smooth transition from the start-up to the process phase that does not require any mechanical intervention of the pressure vessel/burner assembly and can be performed through automatic control systems.

1 . A burner for the partial oxidation of a hydrocarbon feedstock, comprising:
 fuel and oxidizer passages and a premixing chamber, wherein the burner comprises a plurality of annular passages for the feeding of fuel and oxidizer,   said plurality of annular passages comprising at least a first annular passage for feeding a fuel flow, and at least a second annular passage for feeding an oxidizer flow,   said annular passages being coaxial and radially consecutive one to the other, and open in said premixing chamber.   
     
     
         2 . The burner according to  claim 1 , wherein said plurality of annular passages comprises a central annular passage between an inner passage and an outer passage, said central, inner and outer passages being open in said premixing chamber, where the central annular passage is fed with one of the fuel flow and oxidizer flow, and said inner and outer passages are fed with the other of said fuel flow and oxidizer flow, during the operation of the burner. 
     
     
         3 . The burner according to  claim 1 , where at least some of said annular passages have separate inputs and can be fed with streams having different compositions. 
     
     
         4 . The burner according to  claim 1 , wherein the annular passages are delimited by the walls of coaxial annular bodies. 
     
     
         5 . The burner according to  claim 4 , wherein at least one of said bodies of the burner is formed with an internal passage for a cooling medium. 
     
     
         6 . The burner according to  claim 4 , comprising three main elements, namely an inner body, an intermediate body and an outer body, defining a central annular passages and an inner and outer annular passages around said central passage, for the fuel and the oxidizer. 
     
     
         7 . The burner according to  claim 1 , further comprising a start-up burner in a central axial region of said burner, surrounded by said annular passages for the fuel and the oxidizer, said start-up burner being partly or fully integrated with the main burner. 
     
     
         8 . The burner according to  claim 7 , where said start-up burner comprises: a main hub carrying an ignition device, and a swirler;
 an oxidizer passage is defined around said main hub and a fuel passage between the main hub and a pipe;   the start-up burner has a pre-mixing channel at the outlet of said oxidizer and fuel passages, and the swirler is downstream said pre-mixing channel.   
     
     
         9 . The burner according to  claim 8 , comprising an annular body having a surface with a first portion defining a combustion chamber of said burner, and a second portion having a smaller diameter than said first portion, said second portion being shaped to host the start-up burner and to form an outer surface of said oxidizer passage ( 4 ) and pre-mixing channel. 
     
     
         10 . A process for production of a syngas from a hydrocarbon feedstock, where a fuel flow comprising said hydrocarbon and at least one oxidizer flow are fed into a burner, and partially or completely pre-mixed in a premixing chamber of said burner, upstream a combustion chamber, wherein:
 one of said fuel flow and oxidizer flow is fed to said premixing chamber of the burner through at least a first annular passage, and   the other of said fuel flow and oxidizer flow is fed to said premixing chamber through at least a further annular passage coaxial and radially consecutively to the first annular passage,   forming a layered distribution of fuel and oxidizer in said premixing chamber.   
     
     
         11 . The process according to  claim 10 , wherein:
 one of said fuel flow and oxidizer flow is fed to said premixing chamber through a first annular passage of the burner, and   the other of said fuel flow and oxidizer flow is fed to the premixing chamber through an inner passage and an outer passage surrounding the first annular passage.   
     
     
         12 . The process according to  claim 11 , where the fuel flow is fed to the first passage and oxidizer is fed to said inner and outer passages, or oxidizer is fed to the first passage and a fuel flow is fed to said inner and outer passage. 
     
     
         13 . The process according to  claim 12 , where a first oxidizer-containing flow is fed to the inner passage, and a second oxidizer-containing flow is fed to the outer passage surrounding the first fuel passage, said first and second oxidizer-containing flows having a different composition. 
     
     
         14 . The process according to  claim 10 , where the fuel flow is a mixture of said hydrocarbon with another non-combustible medium, preferably steam, and said hydrocarbon is preferably natural gas. 
     
     
         15 . The process for the production of syngas according to  claim 9 , wherein the transition from the start-up phase to the process phase of the burner is performed through automatic control systems with no direct human intervention on the start-up and process burners or on the reactor vessel.